The Pantanal is the largest seasonal wetland in the world with a landscape that consists of a mosaic of permanent aquatic habitats, and floodable and non-floodable savannas, pastures and forests. Drought events are expected to occur more frequently in the Pantanal biome under future climate conditions, but the effects of land management and hydrological extremes on pastures have been poorly studied at spatial scales relevant to local livestock. In this study, we measured CO₂C fluxes using eddy covariance over a hydrological year on pastures within a cattle farm in the Brazilian Pantanal that experienced seasonal flooding. Our measurements show that seasonally flooded pastures were large emitters of CO₂C, contributing 337 g CO₂C m⁻² year⁻¹ to the atmosphere. During flooding, when the soils were anaerobic, and soil O₂ was close to zero, the flooded pasture was a net sink of -18 g CO₂C m⁻², while during the aerobic phase (soil O₂ > 15%) the pasture was a significant CO₂ source to the atmosphere (301 g CO₂C m⁻²). Transitions to and from anaerobic conditions corresponded to 54 g CO₂C m⁻². Our results indicate that the seasonally flooded cattle pastures in the Brazilian Pantanal may be an important regional source of CO₂C for the atmosphere. Better management, and use of drought resistant grasses, may be a way to improve soil C stocks and limit emissions, especially as global climate change is anticipated to increase heating and drying for the Pantanal biome.

潘塔纳尔湿地是世界上最大的季节性湿地，其景观由永久水生栖息地、可淹没和不可淹没的稀树草原、牧场和森林组成。在未来的气候条件下，预计干旱事件将在潘塔纳尔生物群系中更频繁地发生，但在与当地牲畜相关的空间尺度上，土地管理和极端水文对牧场的影响的研究很少。在这项研究中，我们使用涡流协方差在巴西潘塔纳尔的一个养牛场内经历了季节性洪水的牧场上测量了 CO _{2 C 通量。}我们的测量结果表明，季节性被淹的牧场是 CO ₂ C 的大排放源，贡献了 337 g CO ₂ C m ^-2年^-1到大气。淹水期间，当土壤厌氧，土壤O ₂接近于零时，淹水草场净汇-18 g CO ₂ C m ^-2，而在好氧阶段（土壤O ₂ > 15%）牧场是大气中重要的 CO _{2来源（301 g CO 2} C m ^-2）。向和从厌氧条件的转变对应于54 g CO ₂ C m ^-2。我们的研究结果表明，巴西潘塔纳尔湿地季节性被淹的牛牧场可能是 CO _{2的重要区域来源}C为气氛。更好的管理和抗旱草的使用可能是改善土壤碳储量和限制排放的一种方式，尤其是在全球气候变化预计将增加潘塔纳尔生物群落的加热和干燥的情况下。